RSAA Colloquia / Seminars / Feast-of-Facts: Thursday, 18 August 2016, 11:00-12:00; Duffield Lecture Theatre

Jesse van de Sande

"Revisiting galaxy classification with SAMI through high-order stellar kinematics"

The introduction of visible integral field spectrographs in the last decade led to major developments in the kinematic classification of galaxies. From two-dimensional stellar kinematic measurements, the SAURON and ATLAS-3D survey suggested that galaxies can be classified as fast and slow rotators. The very different dynamical properties of these groups suggest that there is more than one formation path for creating early type galaxies. Recent cosmological hydrodynamical simulations suggest, however, that in order to better understand the assembly and merger history of galaxies, the deviations from a Gaussian line of sight velocity distribution have to be studied. In particular the high order kinematic moments h3 (skewness) and h4 (kurtosis) of the lines can be used to decode a galaxy’s cosmological assembly history. In this talk, I will assess these result by using stellar kinematic measurements from the SAMI Galaxy Survey. From the high order moments, we have developed a new method for kinematically classifying galaxies. I will compare our new kinematic classes to other global galaxy properties, and show that this method has real potential for linking the high order moments to the type of mergers galaxies experienced in their past.